"[The shutdown] is very much relevant to us," mapping company CARTO's Stuart Lynn tells CityLab. "We're embedded in the community."

The L serves some transit-light areas

New York City may have the most extensive transit system in the country, but not all neighborhoods are equally transit-rich. Incidentally, the L Train runs through some areas lacking in commuting options.

CARTO's first map below shows the most common streets (within a 30-minute walking distance) that Brooklyn commuters take to their nearest L station. The thicker the pink line in the map, the higher the number of people who walk that path:

In the northwest and southwestern parts of the route, the web of pink lines stretches further out from the stem of the L, suggesting that people walk longer distances to reach the train. CARTO mapmakers also note:

The further east people are located on the L, the more viable alternatives they have to reach Manhattan in the same or similar travel time by changing to another line before the tunnel (e.g., the A at Broadway Junction).

Many low-income households depend on the L

The second map shows the poverty rates in the areas surrounding the L. The lighter purple the block, the higher its share of low-income households.

Overall, the map's creators estimate that 18,889 such families rely on this service. If the D.C. Metro shutdown is any indication, it's these poorer riders that bear the brunt of maintenance shutdowns.

Where help is needed

To take their demographic analysis a step further, CARTO analysts bundled together blocks with similar poverty rates. Bushwick, Brownsville and East New York, and South Williamsburg are among the high-poverty clusters (in purple), per the analysis. Greenpoint, on the other hand, has affluent blocks (in green).

The point of this map is to isolate the areas "that would not have the financial resources and job flexibility to overcome a major transit disruption," the mapmakers write, so that the city can know where to target its assistance during the disruption:

The best alternative routes

Following the announcement of the shutdown, L commuters have been considering their travel options. It's possible that the city will deploy additional buses during the shutdown to shuttle stranded commuters back and forth between Brooklyn and Manhattan.

For the purposes of this map, the folks at CARTO assume that these substitute buses will run between the Lorimer stop in Williamsburg and Union Square in Manhattan. Without traffic, that journey should take about 20 minutes, they estimate.

Based on this scenario, the mapmakers find that most commuters would get to Manhattan quicker if they transferred to a different subway line as soon as possible, instead of taking the bus all the way.

Those who live around the yellow in the map below, for example, would do well to switch to the M train at the Myrtle-Wyckoff stop.

Commuters in the blue region should transfer to the A line at Broadway Junction. Only those living near the five L stations closest to Manhattan would benefit from taking the bus across the Williamsburg Bridge.